This invention relates to an electrical power distribution circuit for electrical power distribution lines and, more particularly, to a disconnect apparatus for switching capacitive currents.
Electrical power distribution systems often include overhead electrical power distribution lines mounted upon poles by a wide variety of mounting structures. Electrical power distribution systems require switching for many reasons, including fault isolation, transfer loads from one source to another, isolation of line segments for purpose of maintenance or new construction, and in some instances for shedding loads. Different loads vary the power factor of the electrical power distribution system. A decrease in the power factor may result in line losses. For example, with a reduction in power factor a distribution company may need to buy substantially greater power capacity than can be supplied, owing to the line losses.
To control the power factor electric power distribution systems may include capacitor banks associated with a utility line. A disconnect switch connects the capacitor banks to the power lines. However, conventional disconnect switches cannot switch capacitive currents. Instead, the conventional disconnect switches are intended to handle primarily resistive loads. Such switches will not interrupt capacitive currents.
The present invention is directed to solving one or more of the problems discussed above in a novel and simple manner.
In accordance with the invention, there is disclosed a disconnect apparatus for switching capacitive currents for electrical power lines.
Broadly, according to one aspect of the invention there is disclosed a disconnect apparatus for electrical power lines comprising a circuit interrupter having a fixed contact and a moveable contact. A linkage mechanism has first and second coupling elements. The second coupling element is secured to the moveable contact for operating the circuit interrupter. A drive mechanism has an output coupling element. An insulator assembly operatively connects the output coupling element to the linkage mechanism first coupling element. The insulator assembly comprises an insulator having a through bore. An insulator rod extends through the bore and is connected between the output coupling element and the linkage mechanism first coupling element. A dielectric seal is located between the insulator and the insulating rod.
It is a feature of the invention that the insulating rod comprises a fiberglass rod.
It is another feature of the invention that the dielectric seal comprises a silicon seal having a dielectric constant in a range of 400 to 600 volts/mil.
It is still another feature of the invention that the dielectric seal comprises a dual layer seal, one of the layers being a relatively firm dielectric gel and the other layer having a relatively high dielectric constant.
There is disclosed in accordance with another aspect of the invention a disconnect apparatus for switching capacitive currents for electrical power lines comprising a circuit interrupter having a fixed contact and a moveable contact. A first terminal connector is electrically connected to the fixed contact for connection to an electrical power line. A second terminal connector is electrically connected to the moveable contact for connection to a capacitive element. An adjustable linkage mechanism has first and second coupling elements and means for adjusting spacing between the first and second coupling elements. The second coupling element is secured to the moveable contact for operating the circuit interrupter. A drive mechanism is operatively connected to the linkage mechanism first coupling element for driving the circuit interrupter.
It is a feature of the invention that the second coupling element comprises a rod secured between the moveable contact and a rod cap of the linkage mechanism, and it is also a feature of the invention that the linkage mechanism included means for adjusting spacing between the first and second coupling elements comprises. The rod secured between the moveable contact and the rod cap is threaded for adjusting spacing between the moveable contact and the rod cap.
It is another feature of the invention that the linkage mechanism comprises a spring providing a clamping force on the second coupling element.
It is yet another feature of the invention that the linkage mechanism comprises a toggle arm hingedly mounted relative to the circuit interrupter and having a first end operatively connected to the first coupling element and a second end connected to a fitting receiving the second coupling element. The fitting comprises a spring providing a clamping force on the second coupling element.
Further features and advantages of the invention will be readily apparent from the specification and from the drawings.